|Information in this article is non-canon|
Yu is a green Velociraptor with blue strikes from his neck down his back and his tail. He has green eyes and white claws.
He's fairly young, same age as his best friend, Rex.
Yu can be simple-minded at times, which might cause him to lose track of some things. He's naturally shy around everyone he meets for the first time, but gain his trust and friendship and he will stand by you no matter the situation, he will always have your back.
He's the sole son of the leader of his pack, the Toviel. Some Velociraptors from their rival pack have tried time and time again to murder Yu, which in one attempt they managed to kill his mother. After so many attempts to kill him, Yu has grown to become aggressive and to attack anyone that tries to get near him, in fear they're with the killers and will attempt to kill him.
He soon grows too used to this, and begins to hate himself for losing control of this habit. Soon he meets Rex and attempts to attack him, And thus his role in the A Sharptooth's Heart series begins...
After meeting and becoming friends with Rex, he has helped him in fitting in with his pack, the Toviel. He later introduces Rex to Chomper after making a sucessful hunt, but their time to know each other was cut short as Bull interfieres. Rex ran off after him and Yu follows, only to lose him shortly afterwards. He later finds him and soon is introduced to Rex's friends, Cera, Petrie, Ducky and Spike. Together, they form a team to find Littlefoot.
It was much more later on when he reunites with the gang in time to catch wind about Rex betraying them, but just like Littlefoot he has his doubts. During their move back to the pack they come accross with Kumo, whom seems to pose a threat to the groupd. Yu, along with Chomper, step forward to defend the group, but fails miserably.
They managed to escape from him, but they just got out of the frying pan and into the fire. Just as they find his pack they find them fighting against their rival pack. Yu is horrified of seeing his father in the fight and telling them to leave, triggering past pains in the Velociraptor. With a quick wish his father won't end up like his mother, Yu leaves with the gang. Soon after they hear a Sharptooth do the Death Roar, a painful roar that is only heard in the final moments of a Sharptooth. The roar brings back past emotions and pains to Yu, but he shakes it off. As luck would have it, they run into Kumo again, and Yu and Chomper step up again to defend, but Kumo lets them leave without a struggle.
After reuniting with Rex, he follows them to the Great Valley walls, finding a hidden entrance to the valley to say his goodbyes to Littlefoot and the rest. Yu returns to the Mysterious Beyond with Chomper and Rex, who decided to stay behind...